Here are the 10 steps common to most Latino residential brothels, according to sex trafficking and law enforcement experts. (Images: Montgomery County, MD Police Department and Department of Homeland Security Immigrations and Customs Enforcement

1. Direct marketing

Brothels ensure a steady stream of customers by advertising aggressively at bus stops, parks and other high traffic pedestrian areas.

After identifying qualified customers (typically Spanish-speaking males), advertisers pass out "tarjetas" — business cards with ads in Spanish for phony products and services like men's cologne or house-call manicures. "Johns" know the ads are for sex. "Squares" likely never give the cards a second thought.

3. Reading between the lines

Some "tarjetas" will have codes - like wings indicating a brothel that delivers. Sometimes a call has to be placed to get the location of a brothel; other times the address is right on the card.

4. Now delivering

If delivery is an option, trusted car services are sometimes involved, with drivers taking a fee. Sometimes employees of the brothel drive girls around. Busy brothels keep long lists of available drivers, who share the profits with the brothel owners.

When a "john" visits a brothel, a "door man" will ask probing questions: "Where are you from?" "Where do you live?" "Where did you hear about us?" If the story and the accent check out, the customer he can gain entrance to the closed-network brothel.

6. The sale

Inside the brothel — usually a normal house or apartment — available girls or waiting "johns" sit on couches in a sparse living room. When a "john's" turn comes he goes to a man called a "ticketero" and hands him money — usually $30 for 15 minutes.

7. The token

The "ticketero" gives the "john" a token (a playing card, a marble, a poker chip or a glass bead). Girls keep the tokens to keep track of how many "johns" they see at the brothel. Even though they keep a count, many girls are not paid.

Depending on the brothel, a "john" can select a girl. Often there are as few as two girls servicing as many as 50 men each in a night, so there are not always options. Ledgers are used to keep track of visits.

9. Behind the curtain

"Johns" follow girls to a room. Often large rooms are divided up by nothing more than hanging sheets. There is rarely anything other than a sparse bed, and products like sanitizer, lubricant, condoms and paper towels within.

10. The sex act

The "john" gives the girl the token, and the 15 minutes begin — sometimes with the turn of an egg timer.